Enzymes And Digestion

Question 1

What are enzymes?

Answer 1

They are proteins that are biological catalyst that speed up the rate of reactions without being used up themselves

Question 2

How are enzymes specific?

Answer 2

Each active site has a unique shape that means that no other substrate can fit into it.

Question 3

Enzyme- ?

Substrate-carbohydrates

Products- ?

Answer 3

Enzyme- carbohydrase

Substrate- carbohydrates

Products- glucose

Question 4

Enzyme-?

Substrate- starch

Products- ?

Answer 4

Enzyme- amylase

Substrate- starch

Products- glucose

Question 5

Enzyme-?

Substrate- proteins

Products- ?

Answer 5

Enzyme- protease

Substrate- protein

Products- amino acids

Question 6

Enzyme- ?

Substrate- fat (lipids)

Products- ?

Answer 6

Enzyme- lipase

Substrate- fat (lipids)

Products- fatty acids and glycerol

Question 7

How is the enzyme complementary to substrate?

Answer 7

The enzyme is complementary as it allows the substrate to fit into the active site

Question 8

Why can enzymes be used over and over again?

Answer 8

Once the substrate fits into the , the reaction take place, and products leave active site

This means that the active site is free and ready to accept a new substrate molecule

So they can be used over and over again

Question 9

What is an inhibitor? And why do they reduce the rate of reactions?

Answer 9

An inhibitor is a molecule that fits (loosely or partially) into the active site of an enzyme.
This means that the active site is blocked and the substrate cannot enter to be broken down as long as the inhibitor is there. Therefore, the rate of reaction is reduced by inhibitors.

Question 10

What is digestion?

Answer 10

The breakdown of big, insoluble particles to small, soluble particles so they can be absorbed into the bloodstream.

Question 11

Explain the function of the mouth in terms of digestion?

Answer 11

• Mechanical digestion by teeth

- Chemical digestion of starch by amylase

Question 12

Explain the function of the stomach?

Answer 12

Makes gastric acid containing

• Protease enzyme (digests protein)
• Acid (optimum pH for protease/ kills germs)

Question 13

Explain the function of the liver?

Answer 13

Makes bile (helps digest fat/neutralises acid)

Question 14

Explain the function of the gall bladder?

Answer 14

Stores bile

Question 15

Explain the function of the pancreas?

Answer 15

Makes enzymes

Question 16

What is the function to duodenum (1st part of small intestine)?

Answer 16

Most digestion occurs here

Question 17

What is the function of the ileum (2nd part of the small intestine)?

Answer 17

Absorption of food into blood

Question 18

What is the function of the colon (large intestine)?

Answer 18

Water absorption

Question 19

What is the function of the Rectum?

Answer 19

Stores faeces

Question 20

What is the function of the anus?

Answer 20

Removes faeces

Question 21

How is the ileum adapted for the absorption of food molecules?

Answer 21

1. Large surface area - long;folded;villi
2. Good blood supply
3. Thin & permeable membranes

Question 22

How is the villus adapted for absorption?

Answer 22

• shape increases surface area
• single layer of cells
• blood capillary network (absorbs products of digestion)
• lacteal (absorbs digested fat)

Question 23

Describe the effect of temperature on enzymes?

Answer 23

As the temperature increases the rate of enzyme activity increases and the molecules have more energy therefore more collisions between enzyme & substrate
Above the optimum temperature the enzyme denatures and the shape of active site changed and the substrate cannot fit into active site and the enzyme no longer works

Question 24

Describe the effect of pH on enzymes?

Answer 24

Either side of the optimum pH enzymes work less well because the pH changes the shape of the active site (denatured)

Question 25

Explain the effect of enzyme concentration?

Answer 25

Increasing the concentration of enzymes only make a faster reaction until a certain point at where there is not enough substrate molecules for the enzymes